Fair Value Measurements (Reconciliation Of Beginning And Ending Balances For Level 3 Investments) (Details) (USD $) In Thousands	9 Months Ended		1 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Oct. 31, 2010 Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2011 Significant Unobservable Inputs (Level 3) [Member]		Dec. 31, 2010 Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance				$ 2,704		$ 3,971
Unrealized loss on securities recorded in other comprehensive income						(167)
Partial/full redemption of auction rate security			(1,100)	(450)	[1]	(1,100)	[1]
Sale of tax-advantage preferred stock				(2,485)	[2]
Realized gain on securities included in the statement of operations				409	[2]
Reversal of unrealized gain on securities sold recorded in other comprehensive income	178	589		(178)
Ending balance						$ 2,704

[1] Level 3 short-term investments as of December 31, 2010 included an auction rate security invested in a tax-exempt state government obligation that was valued at par with a value of $0.4 million, or 0.1% of our total assets. Our intent was not to hold the auction rate security invested in a tax-exempt state government obligation to maturity, but rather to use the interest reset feature to provide liquidity. In October 2010, $1.1 million of this security was redeemed by the issuer at par. Due to continued failures in the marketplace auctions, we held the remaining $0.4 million auction rate security until the maturity date in September 2011, when it was redeemed by the issuer at par.

[2] Level 3 long-term investments as of December 31, 2010 included a tax-advantaged preferred stock of a financial institution with a fair value of $2.3 million, or 0.5% of total assets. As of December 31, 2010, it was uncertain whether we would be able to liquidate these securities within the next twelve months; as such we classified them as long-term on our consolidated balance sheet. Due to the lack of observable market quotes, we utilized valuation models that relied exclusively on Level 3 inputs including those that are based on expected cash flow streams, including assessments of counterparty credit quality, default risk underlying the security, discount rates and overall capital market liquidity. In June 2011, we sold this security for approximately $2.5 million and recorded a gain of approximately $0.4 million in our consolidated statement of operations.